Excited states by analytic continuation of TBA equations
Abstract
We suggest an approach to the problem of finding integral equations for the excited states of an integrable model, starting from the thermodynamic Bethe ansatz equations for its ground state. The idea relies on analytic continuation through complex values of the coupling constant, and an analysis of the monodromies that the equations and their solutions undergo. For the scaling LeeYang model, we find equations in this way for the one and twoparticle states in the spinzero sector, and suggest various generalisations. Numerical results show excellent agreement with the truncated conformal space approach, and we also treat some of the ultraviolet and infrared asymptotics analytically.
 Publication:

Nuclear Physics B
 Pub Date:
 February 1996
 DOI:
 10.1016/S05503213(96)005160
 arXiv:
 arXiv:hepth/9607167
 Bibcode:
 1996NuPhB.482..639D
 Keywords:

 High Energy Physics  Theory
 EPrint:
 25 pages, latex, 6 ps files, uses epsf.tex. Typos corrected